Thread gage setting or clamping device



p 1966 s. G. JOHNSON 3,270,427

THREAD GAGE SETTING 0R CLAMPING DEVICE Filed Aug. 5, 1963 2 Sheets-Sheetl l/l/ H *7 32 I 5 32 28 CHUCK 5 i :Y 45 37 43 l.*'-

F 4. i 42 44 39 J. 47

1 UV 7 l NTOR STAN G. JOHNSON ATTORNEY.

p 1966 s. G. JOHNSON 3,270,427

THREAD GAGE SETTING OR CLAMPING DEVICE Filed Aug. 5, 1963 2 Sheets-Sheet2 FIG. 6.

2 INVENTOR. STANLEY G. JOHNSON ATTORNEY United States Patent 3,270,427THREAD GAGE SETTING OR CLAMPING DEVICE Stanley G. Johnson, WestHartford, Conn, assignor to The Johnson Gage Company, Bloomfield, Coun.,a corporation of Connecticut Filed Aug. 5, 1963. Ser. No. 300,020Claims. (Cl. 33199) The invention relates to a thread gage setting,clamping and thread testing device which is applicable to internalthreads or external threads, although the economic factors of the deviceas a gage setting means appears to be greater and more material withrespect to an expandible thread plug gage having external threads. For athread gage setting device to be used to set an expandible thread pluggage, the setting device is a thread ring means with internal threadswhich is adjustable over a relatively narrow range that is a range forone thread solely but with different tolerances.

An object of the invention is to construct a thread gage setting deviceusing two members, each member having a thread of the same size andpitch and in axial alignment and one member being rotatable with respectto the other and to which is applied a frictional drag for assuring thatthe setting device holds its setting.

Another object is to construct a thread clamping device as described inthe preceding paragraph for clamping the thread of a threaded part inwhich the frictional drag provides more positive clamping of a threadedpart so that another surface or surfaces on the part may be processedsquare and/or concentric with respect to the thread on the part.

A more particular object is to construct an adjustable thread gagesetting device or thread ring device of two members with one memberbeing rotatable with respect to the other and each having a thread ofthe same size and pitch and in axial alignment which can be set with arelatively inexpensive master thread plug and held set so that theringgage setting device may then be used for setting an expandible threadplug gage to proper size for gaging threaded holes.

Another object is to construct a device for measuring the wear on a pluggage of the solid and expandible type.

Other objects of the invention will be more apparent from the followingdescription when taken in connection with the accompanying drawingsillustrating preferred embodiments thereof in which:

FIG. 1 is a section through a thread gage setting and clamping devicehaving an internal thread;

FIG. 2 is an adjusting wrench for the device;

FIG. 3 is a section through the device serving as a thread clampingmeans to grip the thread of a threaded part.

FIG. 4 shows a like device constructed with external threads.

FIG. 5 is a section of the rings with a master plug.

FIG. 6 is a section'of the rings with a worn thread plug thereinengaging one flank.

FIG. 7 is a section of the rings with a worn thread plug thereinengaging the other thread flank.

FIG. 8 is a view of a scale carried by the device.

The device illustrated in FIG. 1 includes a frame member which could beone part, however manufacturing convenience makes it desirable to be asparticularly shown. The frame member is made up of three parts includingan end plate 10, a first or fixed ring 11 having an internal thread 12and secured to the end plate by screws 13. The frame also includes acase 14 having a bore 15 which receives the ring 11.

3,270,427 Patented Sept. 6, 1966 "ice A second or cooperating member isa ring 18 which is mounted in the bore 15 of the case 14 for rotation orangular displacement or adjustment with respect to the ring 11. Thecooperating ring 18 has an internal thread 19 which is of the same sizeas the thread 12 and of the same pitch and is in alignment therewith.The cooperating ring 18 may be adujsted rotatively relatively to ring 11by any suitable means, that illustrated including holes 20 in the outerface thereof for receiving pins 21 carried by an adjusting wrench 22.

Means are provided to apply a frictional drag on the cooperating ringsufficient to keep this ring in adjusted position. The frictional meansshown is combined with an end or friction plate 25 secured to the framemember by screws 26, which screws also secure the casing to the plate10. Angularly spaced screws 26 are shown. The end plate has a retainingand friction portion 27 extending inwardly which engages or overlaps theouter face of the cooperating ring 18 so that it also retains thecooperating ring in the frame member.

The frictional drag may be secured by making the combined width of rings11 and 18 slightly greater than the width of the case 14 say about A ofan inch so that when the screws 26 are tightened, the portion 27 of thering 18 presses against the outer face of the cooperating ring 18 andestablishes a frictional drag therebetween as Well as pressing the innerface of the cooperating ring against the abutting face of the ring 11 sothat there is also frictional drag on the abutting face of the ring 18.In order to avoid precise manufacture, a better construction is to taperinwardly the end face 28 of the case 14 by about 1 degree and make thecombined widths of the rings 11 and 13, about 1- or 2-thousandths of aninch less than the width of the casing. The end plate 25 has sufiicientflexibility to fri'ctionally engage the end face of the ring 18 forexample for a one quarter inch thread the clamping plate is aboutone-sixteenth of an inch thick. In other words in the constructionparticularly shown the rotatable cooperating ring is lightly clampedbetween the ring 18 and the end or friction plate.

In using the device for setting an expandible thread plug gage, a masterthreaded plug of the desired thread size is threaded into the thread 12,19 and the cooperating ring or member 18 is then rotated with respect tothe frame member until the thread 12, 19 removably or lightly binds themaster thread plug with the thread of one ring engaging one flank of thethread of the master thread plug and the thread of the other ringengaging the other flank of the master. The master plug is thenunscrewed from the thread 12, 19 and the gage setting device has theproper size for setting an expandible thread plug gage. The frictionaldrag provided on the rotatable cooperating member 18 is suflicient toretain this member in its set position against inadvertent changing ofthe setting such as would occur when the master thread plug isunthreaded from the gage setting device if there were no or insufficientfrictional drag to hold the setting.

Using the device as a clamping means for holding a manufactured threadedpart P for additional processing is illustrated in FIG. 3. The threaddevice used as a thread clamping means is secured such as by a screw orspaced screws S in a chuck or socket means which has a bore B thereinand an end face EF at the bottom of the bore. The face EF is accuratelysquare with respect to the axis of the bore. The end face 30 of thethread clamping device is accurately square with respect to the axis ofthe threads 12, 19 and when engaging the end face EF of the bore, it isknown that the axis of the thread 12, 19 is at right angles to the axisof the chuck or the 120" apart in the case.

face EF. The surface S1 of the part P may then be ground or lapped withassurance that the surface will be processed square with respect to theaxis of the thread on the part P.

The part P is threaded into the thread 12, 19 of the frame member andcooperating member whereupon the cooperating member 18 is rotated untilthe thread of the port is gripped on one flank by the thread 12 and onthe other flank by the thread '19. The frictional drag provided on therotatable cooperating member 18 with the friction means or clampingplate assures that under the processing there will be no unloosening ofthe part be cause there is superimposed upon the gripping action of thethreads 12, 19 on the thread of the part P, the additional frictionaldrag imposed against rotation or unloosening applied by the rotatablecooperating member 18. It will "be noted that if the clamping actionwere solely in the threads 12, 19 that this clamping action is on ahelix or inclined plane of the thread which may tend to unloosen thesame when the part is being processed whereas the frictional drag on therotatable cooperating member 18 is the same at all times, and added tothe gripping action on the threads of the part.

- Often times concentricity is desired of the surface S2 or S3 withrespect to the axis of the thread on the part P. If this is theprocessing to be performed on the part P then the peripheral surface 31of the frame of the device is accurately ground concentric with respectto the axis of the thread 12, 19. The bore of the chuck or socket ismade accurately concentric with the axis of the chuck. The grippingaction of the threads 12, 19 centers the thread of the part on the axisof the threads 12, 19. When the surface S2 of the part P is then ground,lapped, or otherwise processed, it is known that this surface isconcentric with the axis of the thread of the part P. If both squarenessand concentricity of surfaces with respect to the thread of the part isdesired, then the face EF of the chuck is made square with respect toits axis and the bore B is made concentric with respect to the axis ofthe chuck. The part P may have either an external cone or an internalcone S3 as shown in dot-dash lines which must be accurately processedconcentric with the thread of the part. The thread clamping deviceassures that such conical surface on part P will 'be accuratelyconcentric with the axis of the thread of the part. The part P may haveany one or more of the surfaces mentioned for processing.

If the threaded rings 11 and 18 should not be in precise alignment withthe exterior surface or periphery of the device it can be adjustedthrough adjusting screws 32 carried by the case 14, three of whichscrews are located The end of the screw engages the periphery of the twothread rings or members and will shift and lock them in position withthe periphery of the case or frame member in alignment with the threadaxis.

In the construction of FIG. 4, a gage setting and clamp ing device isillustrated with an external thread for setting a contractible internalthread gage or for holding a part P1 With an internal thread for furtherprocessing of another surface or surfaces, such as grinding or lapping,so that the surface is or surfaces are square and/ or concentric withrespect to the axis of the thread of the part. This device comprises aframe member 35 having an external screw thread 38 and a co-operatingmember 42 which is rotatable with respect thereto and has an externalscrew thread 43. The frame member includes a mounting means 36 and aseparate threaded ring 37 received on the mounting means although theparts 35 and 37 may be one part. The ring 37 has an external thread 38.The ring is secured to the spindle 35 by the screws 39 so that the framemember could be an integral member if desired.

A co-operating ring 42 is also received on the mounting means 36, and isrotatable thereon. The co-operating ring has an external thread 43 whichis the same size and pitch and in alignment with the thread 38. Thecooperating ring 42, is turned on the mounting means such as through theholes 44, which receive the wrench of FIG. 2.

A drag means is provided to apply frictional pressure on the cooperatingmember. The manner in which this may be provided in the constructionillustrated, is to make the length of the mounting means 36, slightlyless than the combined widths of the rings 37 and 42, so that the outerface of the cooperating member extends slightly beyond the end of themounting means, such as fi th of an inch. A clamp and retaining plate 47has an outer portion thereof engaging the front face of the cooperatingring 42. The plate 47 is attached to the frame member or particularly tothe mounting means 36 such as by a screw 48, so that tightening of thescrew 48 brings the outer portion of the clamp plate 47 into frictionalcontact with the face of the cooperating member 42 and also presses theabutting faces of the two rings into frictional contact to give thedesired drag on the cooperating ring. The end face of the mounting meansmay be tapered or inclined as in the construction of FIGS. 1 and 3 ifdesired.

A part P to be processed is threaded onto the thread 38, 43 after whichthe cooperating ring 42 is turned so that thethread 38 engages one flankof the thread on the part P1 and thread 43 engages the other flank ofthe internal thread of the part to clamp or grip the part thereon. Thefrictional drag on the cooperating ring 42 augments or is added to thegripping or clamping action on the thread to assure a firm grip on thethread for processing of at least one other surface such as S1, S2 andS3 of the part.

It is desired to have the face S1 square with respect to the internalthread of the part, the end face 41 of the frame member is accuratelysquare with respect to the axis of the thread 38. With the bottom of thebore of the chuck accurately square with respect to its axis and withthe end face 41 engaging the bottom of the bore it is known that theclamping device and its thread 38, 43 is square with the respect of theaxis to the chuck. The face S1 of the part P may then be processed andit will be square with respect to the internal threads of the part P.

If it is desired to have the surfaces S2 and/ or S3 of the part Pconcentric with respect to the axis of the internal thread, then theperiphery 45 of the frame member 35 is accurately ground concentric withthe axis of the thread and the bore B of the chuck is ground concentricwith the axis of the chuck, so that when the frame member is mountedtherein, it is known that the axis of the frame member is concentrictherewith. The surface S2 or S3 or both when ground will be concentricwith the internal thread of the part P1. It is clear that with thebottom or end face EF of the bore square with respect to the axisv ofthe chuck and the bore B being concentric with the axis of. the chuck,then surface S1 may be processed square with respect to the axis of theinternal thread, and the surfaces S2 and S3 when processed Will beconcentric with the internal thread of the part.

The externally threaded device may be used for setting a contractiblethread gage, however, the economic factor is not as favorable as with anexternal thread because such gage can be set on a solid thread plug. Asa clamping device for gripping a threaded part for additional processingto secure a surface which is square with respect to the thread of thepart and/ or one or more surfaces which are concentric with respect tothe thread of the part, it has all of the advantages of the internallythreaded clamping device. The gage setting and clamping device by virtueof its construction will also compensate for a slight taper in thethread of the part P or P1. For a setting and clamping device for aquarter inch thread a frictional drag of about 3 inch pounds issatisfactory. For larger sizes of threads the frictional drag should begreater. The number of threads 19 or 43 is of no particular importanceand may be one thread on each ring or any greater number of threads.

FIGS. 5 to 8 illustrate an additional feature in the device, the purposeof which is to test a thread plug gage either of the expandible or solidtype, as to the wear which has occurred in the thread as a consequenceof use. Heretofore, a solid thread plug gage was commonly tested forwear by threading the same into a master ring of minimum allowablediameter and shaking the same therein. If there is shake or the shakewas deemed to be too great the plug was discarded. Obviously this testdepends upon the judgment of the person and is not a particularlyreliable method of determining the extent of wear. An expandible threadplug gage cannot be tested in a simple way and may require expensiveequipment such as a projection tester. Usually the wear in both types ofthread plugs is a minimum at the roots of the thread and may besubstantial, in a gage sense, at the peaks of the thread.

'FIGS. 5 to 8 illustrate threaded rings 11a and 18a which may besubstituted for the rings 11 and 18 in the case 14 of FIG. 1. These tworings are identical with rings 11 and 18 in every respect excepting thatthe internal thread on one flank of one ring 11a is relieved or cut awayat '50 from the peak of the thread to a point at or roughly about thepitch diameter. The opposite flank of the other ring 18a is similarlyrelieved at 51. This relief is on one flank only of the thread of eachring and the other flank of each thread helix is a full flank. Theamount of the relief provided need be only about a few thousandths of aninch, such as .002 more or less and may be somewhat greater for largersizes. The relief is enough to enable the maximum allowable wear to bemeasured.

The device of FIG. 1 so modified will now test for wear which hasoccurred from use of a thread plug gage. The test is secured byinserting a master plug and turning the rotatable ring in bothdirections and noting the two readings on scale 52. 'It will 'be notedin FIG. 5 that the relieved flank does not affect the reading with athread master. The plug to be tested is then inserted and the rotatablering 18a is turned in the same direction, as shown in FIG. 6, so thatthe flank of the thread of the plug being tested engages the full flankof each ring and a reading taken on the scale 52 of the angular movementof the ring. This reading provides a comparison with the scale readingfor the master plug. The rotatable wing 18a is then turned in theopposite direction until the worn thread plug is engaged by the relievedflanks of the two rings as shown in FIG. 7 and because of the relief andthe wear, the thread of the test plug excludes that por tion of thethread which has minimum or no wear and as a consequence of this thering has to be turned farther before the relieved flank of the thread ofthe rings will engage the flank of the thread of the thread plug undertest. A comparison with the first reading as to the extent of angularmovement greater than that for both the test plug and the master plugwill indicate the gage is worn and the amount of this wear and at aboutthe pitch diameter. These two readings on the test plug when comparedwith similar readings made with the master plug will give a good pictureof the extent of wear in the sol-id thread plug being tested. A fairindication of wear would be given by the relative scale readings of thetwo tests on the worn test plug alone.

For testing an expandible thread plug gage for wear, a master threadplug is threaded into the rings and the rotatable ring is rotated firstin one direction until the full flanks engage the master thread plug.With this setting the device has the gaging elements of the expandibleplug gage inserted therein and expanded and the reading noted on thedial indicator thereof. The master thread plug is .again threaded intothe device and the rotatable ring is rotated in the opposite directionto bring the relief flank of the two rings into engagement with themaster plug. As shown in FIG. 5 the peaks of the thread of the masterplug control the position of the rotatable ring. The master plug isremoved and the expandible thread gage is inserted in the device andexpanded and the indicator reading noted. The difference between thisreading and the reading from the first reading provides a reasonablyaccurate indication of the wear in the expandible thread plug gage.

It is clear that the same relief may be provided on one flank of thering 37 and on the opposite flank of the thread of the ring 42 in whichevent the device of FIG. 4, may be used to test the wear in a ring gageeither of the solid type or of the expandible type in the same manner asdescribed.

The scale of FIG. 8 may be provided on the end face of one of the partsnamely the rotatable ring 18a or the friction plate 25 and a zero markon the other part. In FIG. 8, the scale is shown as being on the face ofthe ring 18a.

Although the construction of FIGS. 5 to 8 can be used as a clamp thereis no useful purpose in the relieved thread in a clamping use.

This invention is presented to fill a need for improvements in ThreadGage Setting, Clamping and Testing Device. It is understood that variousmodifications in structure, as well as changes in mode of operation,assembly, and manner of use, may and often do occur to those skilled inthe art, especially after benefitting from the teachings of aninvention. This disclosure illustrates the preferred means of embodyingthe invention in useful form.

What is claimed is:

1. A thread gage setting and clamping device comprising a frame member,a cooperating member, each member having a screw thread of the same size:and pitch and with their axes in axial alignment, mounting meanscarried by the frame member to mount the cooperating member thereonsolely for rotation on the thread axis as a center, friction meanscarried by the frame member and engaging the cooperating member andapplying a frictional drag of a fixed amount on the cooperating memberagainst relative rotation with respect to the frame member :and in allrotary positions, and the frictional drag being of the order of 'threeinch pounds for a thread of a quarter of an inch in size and beingprogressively greater for larger diameters, .and circumferenti-allyspaced screw adjusting means carried by the frame member and engagingthe peripheries of the two members.

2. A thread gage setting device to be used with a master threadedelement and clamping device comprising a frame member having acylindrical bearing fOlIIling a mounting means, a first ring membercarried on the mounting means and secured to the frame member, acooperating rin g member, each ring member having a screw thread of thesame size and pitch and with their .axes in axial alignment, thecooperating ring member being mounted on the mounting means solely forrotation on the thread axis as a center, the cooperating ring memberhaving a dimension such that it projects a fixed minute amount beyondthe end of the frame member, friction means carried by the end of theframe member and having a radial dimension overlapping and engaging anend of the cooperating ring member around a complete circular portion ofthe said member and to retain said member on the frame member, screwmeans carried by the end of the frame member irnmovably securing thefriction means thereto so that the overlapping portion of the frictionmeans pressure engages the cooperating member, the friction means havinga flexibility to movably clamp the cooperating member between thefriction means and the first ring member to apply a frictional drag uponthe cooperating member of a fixed and constant amount against relativerotation with respect to the first ring member and in all rotativepositions of the cooperating ring member, and the flexibility being suchthat the cooperating member is readily rotatable on the mounting meansfor adjustment but with sufficient frictional drag or resistance toretain the same in adjusted position against threaded withdrawal of amaster thread element.

3. A thread gage setting and clamping device as in claim 2 in which theframe member comprises a spindle, mounting means carried by the spindle,a first ring secured to the spindle on the mounting means and carryingthe aforesaid thread, the thread being an external thread, thecooperating member having an external thread, the mounting means havinga length slightly less than the combined width of the two rings, thefriction means being a friction plate secured to the end of the spindleand having a portion engaging the end face of the cooperating ringwhereby the friction plate rotatively and frictionally engages thecooperating ring between the first ring and the clamping plate.

, 4. A thread gage setting and clamping device as in claim 2 in whichthe frame member comprises an end plate, the second ring being securedto the end plate and carrying the aforesaid thread, the thread being aninternal thread, a casing secured to the end plate having a borereceiving the ring, and providing mounting means therefor, thecooperating member being a ring received in the bore of the casing andits thread being an internal 25 thread, the friction means being afriction plate carried by the end of the casing and engaging thecooperating ring, the casing having a width slightly less than thecombined width of the two rings whereby the friction plate rotativelyand frictionally clamps the cooperating ring between the first ring andthe clamping plate.

5. A thread gage setting clamping and testing device as in claim 4 inwhich one flank of the thread of one ring is relieved from the peak ofthe thread to the region of the pitch diameter, and the opposite flankof the other ring is relieved a like amount from the peak of the threadto the region of the pitch diameter.

References Cited by the Examiner UNITED STATES PATENTS 500,748 7/ 1893Smith 279-7 761,348 5/1904 Baines 279-7 X 1,120,530 12/1914 Pieper.1,905,705 4/1933 Hartness 33-199 2,782,521 2/1957 Parker 33-1992,792,230 5/ 1957 Schober 279-7 FOREIGN PATENTS 120,307 11/ 1918 GreatBritain.

LEONARD FORMAN, Primary Examiner. ISAAC LISANN, Examiner.

JOHN D. BOOS, Assistant Examiner.

1. A THREAD GAGE SETTING AND CLAMPING DEVICE COMPRISING A FRAME MEMBER,A COOPERATING MEMBER, EACH MEMBER HAVING A SCREW THREAD OF THE SAME SIZEAND PITCH AND WITH THEIR AXES IN AXIAL ALIGNMENT, MOUNTING MEANS CARRIEDBY THE FRAME MEMBER TO MOUNT THE COOPERATING MEMBER THEREON SOLELY FORROTATION ON THE THREAD AXIS AS A CENTER, FRICTION MEANS CARRIED BY THEFRAME MEMBER AND ENGAGING THE COOPERATING MEMBER AND APPLYING AFRICTIONAL DRAG OF A FIXED AMOUNT ON THE COOPERATING MEMBER AGAINSTRELATIVE ROTATION WITH RESPECT TO THE FRAME MEMBER AND IN ALL ROTARYPOSITIONS, AND THE FRICTIONAL DRAG BEING OF THE ORDER OF THREE INCHPOUNDS FOR A THREAD OF A QUARTER OF AN INCH IN SIZE AND BEINGPROGRESSIVELY GREATER FOR LARGER DIAMETERS, AND CIRCUMFERENTIALLY SPACEDSCREW ADJUSTING MEANS CARRIED BY THE FRAME MEMBER AND ENGAGING THEPERIPHERIES OF THE TWO MEMBERS.